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Applied Physics Posts

Quantum-ready engineering

The engineers and scientists we are educating at Stanford today will drive technology development for the next thirty years. Very few of them will ever have an opportunity for substantial renewal of their core knowledge base after they leave graduate school with a Ph.D.

Looking to the future, it is hard to imagine that forefront technology and engineering could progress another ten or twenty years without experiencing some bombshell revolutions. Issues related to globalization and to the environment have recently flared onto our radar screens and are bound to remain there for the foreseeable future; businesses and universities are scrambling to anticipate and to adapt. But another broad class of challenges—which will likewise demand systemic response, yet are much harder to assess managerially—are beginning to come into focus as we contemplate the long term outlook for high-performance yet energy-efficient computation and communication, and as a growing list of industries get serious about grappling with nanotechnology. These challenges are purely intellectual in nature, fall squarely within the scope of academia’s educational mission, and are hallmarks of a major turning point in the modern development of engineering and applied science.

That turning point will be the transition, in certain key sectors, from classical to quantum technologies. This shift may well be gradual and might not begin in earnest for ten or twenty years, but current expert opinion already deems it inevitable. The underlying quantum nature of the physical carriers of information in computers and communication networks—electrons and photons—cannot remain hidden forever as our relentless demand for speed drives engineers to deploy ever-smaller transistors, and to exploit ever-fainter and more fleeting blips of light in fiber-optic networks. We can already count the number of dopant atoms in a state-of-the-art transistor and the number of photons required to represent a bit of information in an optical communication link (a few dozen in both cases). Unfortunately, such extreme frugality in the physical resource allotment per information-processing element generally comes at the price of increased fluctuations and a propensity for soft defects. From a classical-engineering perspective this is a significant obstacle of fundamentally quantum-mechanical origin that signposts the technology roadmap right where Moore’s Law falls by the wayside.

But from the perspective of quantum engineering, the advent of such small-is-different complexities marks the opening of avenues toward radically new paradigms of functionalizing matter and energy with atomic resolution. New engineering concepts and methodology are possible, and indeed required at atomic scale because the physical dynamics of isolated microscopic systems are so qualitatively different from those upon which our macroscopic inventions have relied. Forerunners of true quantum engineering can be seen in the now-ubiquitous laser and in the atomic clock, which plays a key role in enabling modern systems for navigation and geodesy. We have seen our first hints regarding the long-term promise of quantum engineering in the celebrated theoretical results of quantum computation, which show that fundamentally different and superior algorithms can be posited for critical tasks such as factoring. This last revelation has already found its way into best-selling works of science fiction.

Within academia, the revolutionary ideas emerging from early research in quantum engineering have inspired the creation of numerous centers and faculty groups at leading universities; all this in an era when the actual construction of a sizeable quantum information processor remains a futuristic dream. Indeed, in practical terms the path forward is still rather murky as pure quantum behavior is quite difficult to achieve in the rudimentary constructs within reach of current technical capabilities in fabrication and control. The devices we can so-far produce tend to exhibit a gray mix of quantum and classical dynamics, with non-classical phenomena prominent only on very short timescales or over very short length-scales. The development of broadly applicable strategies for promoting and stabilizing pure quantum behavior in devices of useful size is a daunting technical challenge that could require decades of intensive work. As a result, despite the highly disruptive impact that the quantum revolution will ultimately have, companies in high-tech industries have generally adopted a wait-and-see attitude rather than rushing into any major immediate investments. But scientifically we know that the classical-quantum technology transition is there, a manifest destiny just waiting to be reached.

Universities and foundations that can afford to take a long-term view have recognized this, and quantum engineering activities are growing increasingly prominent in worldwide basic research. We believe that Stanford, as a leading institution of higher learning that upholds the integration of education and research as a guiding principle, can take a pioneering role in leveraging such visionary inquiry to inform the way we train our graduate students in participating fields. As the engineers and scientists we are educating today will drive technology development for the next thirty years, they will almost certainly be main players in actualizing the transition to quantum technologies.